<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="wodtj=device-width,initial-scale=1.0">
	<title>作业</title>
</head>
<body>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
         /* 当为嵌套标签时，margin: 0 auto; 实现盒子水平居中  */
        .box {
            width: 800px;
            height: 200px;
            background-color: skyblue;
        }

        .box .son {
            width: 200px;
            height: 200px;
            background: pink;
            margin: 0 auto;
        }
    </style>
</body>
</html>

